【摘要】 为提高陕北黄土区土壤肥力,加快植被恢复与重建,通过测定分析陕西吴起合沟流域原状坡、塌陷、切沟、缓台、浅沟及陡坎6种微地形0～100 cm土层土壤养分变化特征,并采用改进的内梅罗综合指数法综合评价其土壤肥力水平。结果表明,不同微地形0～100 cm土层土壤pH值、有机质、碱解N、全N、有效P和速效K含量变化范围分别为7.84～8.36、0.40%～0.90%、27.86～45.24 mg·kg^-1、0.31～0.53 g·kg^-1、4.66～9.55 mg·kg^-1和152.52～198.02 mg·kg^-1。随着土层深度的增加,各微地形土壤pH值呈上升趋势,有机质、碱解N和全N含量逐渐降低,有效P含量先降低后增加,速效K未呈现一致的变化规律。除陡坎外,不同微地形土壤肥力随着土层深度的增加而逐渐降低。切沟表层（0～20 cm）土壤肥力指数为1.996,达到肥沃水平;原状坡、塌陷、缓台和浅沟土壤肥力指数分别为1.224、0.992、1.148和1.365,均处于一般水平;陡坎土壤肥力指数则为0.695,处于贫瘠水平。各微地形在20～100 cm土层土壤肥力指数差异较小,基本均处贫瘠水平。综合而言,不同微地形土壤肥力呈现出明显的表聚效应,切沟表层土壤肥力最好,陡坎最差,其中有机质、碱解氮、全氮是土壤肥力较低的主要限制因子。更多还原

【Abstract】 This paper characterized the variations of soil nutrients in 0-100 cm soil layer of 6 different kinds of micro-topography in terms of undisturbed slope,collapse,gully,platform,shallow gully and scarp,located at Hegou catchment in Wuqi County of Shaanxi Province,with an attempt to figure out a strategy in improving soil fertility,accelerating vegetation restoration and reconstruction in local loess region.The soil fertility level was evaluated by the method of modified Nemerow integral index.The results showed that the soil pH,the contents of organic matter,alkaline nitrogen,total nitrogen,available phosphorus and available potassium in 0-100 cm soil layer of different micro-topography ranged between 7.84-8.36,0.40%-0.90%,27.86-45.24 mg·kg^-1,0.31-0.53 g·kg^-1,4.66-9.55 mg·kg^-1 and 152.52-198.02 mg·kg^-1,respectively.With the increase of soil depth,the soil pH values in all micro-topography gradually increased,while the contents of organic matter,alkali-hydrolyzed nitrogen and total nitrogen gradually decreased; the available phosphorus decreased first and then increased.However,the available potassium concentrations in different layers fluctuated disorderly.The soil fertility of different micro-topography decreased with the increase of soil depth except the scarp.The soil fertility index of the gully in surface layer（0-20 cm） was 1.996,reaching up the level of ‘fertile’.The soil fertility index of undisturbed slope,collapse,platform and shallow gully were 1.224,0.992,1.148 and 1.365,respectively,which all were regarded as ‘normal’ level.The lowest fertility index was found in the scarp with a value of 0.695,which belonged to barren level.According to the fertility index of 20-100 cm soil layer of different micro-topography,all soils were at barren level.In conclusion,obvious surface aggregation effect of soil fertility were showed in different micro-topography.The soil fertility of gully in surface layer was the best while the scarp was the worst,mainly determined by the main limiting factors including organic matter,alkaline nitrogen and total nitrogen.更多还原